Just wanted to share my thoughts, as I've been using the PMX 680 on my runs for about a week now. After a couple months with a half dozen IEMs, my search is over. While IEMs offer better isolation, the PMX 680 removes the bone transmission "thump thump" completely. It's a tradeoff I'm totally comfortable with, though I confess I altered my route to keep me away from PCH and 60 mph traffic.

I admit I had very high hopes for these. When I first tried them on, my heart sank. They wouldn't stay put over my sunglasses, which are admittedly pretty monstrous.

The next day I tried running with them sans-sunglasses, and without the black foam pads covering the earpieces. I figured they'd stick better with the plastic directly on my ears. After carefully reviewing the directions on how to wear them, I got them to stay in place, but the sound was super bass heavy with rolled off highs.

The next run, I put the foam pads back on at it was much better. I figured out that I needed to tilt them differently, forward and down as far as they'd go while staying flush with my ears. That position allows the highs passage through my ear canal, and the sound is very balanced, maybe even a little bright for some.

Believe it or not, I can wear these upside-down (with the cord coming from the right side), and they stay put and sound great.

IMHO the PMX 680 is about the best you can do in a running headphone. Still, if you're running around heavy traffic, or on a very windy day, it may not be worth the trouble.

Just got my CX680i's yesterday and took them to the gym. My gym is really noisy and usually have to listen to stuff at 1/2 (music) to 3/4 (movies) volume on my iPhone. I have been using Klipsch Image 4si, and they've been great with the oval eartips, but I have to keep adjusting them as they don't stay in well, especially when sweaty, and they eartips seem to come off too easily now.

Anyhow, I happy to report a very positive experience with the CX680's. I opted for the microphone version because the volume control looked nicer to me than the non-mic model, I also occasionally get the call from the wife wondering when I'm going to be home :)

The sound quality on these are very decent, very nice overall. Not to thin on the bass, not to harsh on the highs, just balanced well with enough detail. I've gone through my share of high-end phones and I was prepared to be disappointed, but these held up well enough.

I did have some cable thump, which comes from the wires above the split, so I used the tightener to cinch it up to my neck a little and it stopped the cables from bouncing around and sounded perfect. I've never used that before on any of my phones, but I found it finally came in handy.

I used them for a solid hour, music and movie watching, and they stayed snug the whole time. Overall I'm really happy with them. If I could change anything about them it would be the cable color, but I'm sure I'll get used to it.

These are the "in-ear" model, which is what I wanted for at the gym. If I were running or outdoors exercising I would opted for the earbud variety. I've never had much luck with styles that wraps around the back (like the PMX 680) due to my sunglasses.

I'm looking to get a new pair of headphones for the gym and trying to decide between the CX680s and PMX 680s. They'd mostly be used for watching things on my iPad while running on the treadmill or cycling. I don't need to worry about sound isolation a ton but would prefer to find a set that won't have a lot of cable rub. Which pair would be better suited to my purpose? Or is there another set that would be even better?